Operates on both 120 and 240V.Can be shipped to any country; you can find shipping costs by putting the item into the shopping cart; be sure to click "display rates"

No dangerous metal 240/120 volt lights.

Welcome to algae scrubbers. We are the only source for patent pending waterfall scrubbers that use our new dome/tray combination. All the oceans, reefs, lakes and rivers are naturally filtered only by algae, and all organic particles remain in these waters to feed the animals. Reduce your glass cleaning and water changes, and create an environment for living micro-animals to grow inside the scrubber. No more dosing or possible overdosing of chemicals. No more refilling media. No more pale corals from low nutrients, and no more sick animals from high nutrients. Far more powerful than chaeto or refugiums, and does not remove any food particles. And you can use the algae as food!

The RAIN2 will do most of the filtering needed for your saltwater aquarium, and in most cases it will do all the filtering if it is the proper size for your amount of feeding that you do and the amount of rock that you have. Part of this filtering includes helping eliminate two very important things that drive most aquarium owners crazy: Algae and waterchanges. The filter works by growing algae on the screen, and these algae consume all the "bad" things out of the water*. This is how all the oceans, and all the lakes, are naturally filtered.

Because of the high filtering photosynthesis of our scrubbers, it's not recommended to run them with macro refugiums or chaeto reactors, because the macro or chaeto will die and the nutrients will be absorbed by our scrubbers.

From the inventor of the original waterfall algae scrubber in the year 2008 finally comes a new version: the patent pending RAIN2. The underwater submersible GEM5 lights (also patent pending) allow the RAIN2 to be placed in your sump anywhere you like, as low to the water as you like, which saves a lot of space. And the optional pole mount [here] means you don't even need a shelf or a bracket to place the RAIN2; just use the pole mount to set on the bottom of your sump. You can fit two RAIN2 units into the same space that other waterfall algae scrubbers take for just one of their units.

Safety is a prime concern, and our GEM5 lights keep the 240 or 120 volts far away (2 meters way), with only a safe low voltage going into your sump area. The system is so safe that you could cut the GEM5 lights in half and put them in saltwater and nothing would happen. Other waterfall scrubbers, however, use "waterproof" Chinese lights that are bolted onto the outside of the scrubber box. Not only are these lights not waterproof (don't ever put them in water), they are not even water resistant, and salt creep will eventually get inside them.

Also included is a 2 mm thick, 2 sided, patent pending Green Grabber® algae attachment screen. The screen is also sold separatelyHEREfor DIY, and it is the modern replacement for the old hand-scrapped plastic screens. It is 3D printed in Rough 3D(TM) and has far more algal-attachment surface area than hand-scraped screens. Also, similar to our air bubbling upflow UAS scrubbers, the screen of the RAIN2 is surrounded by air so that when algae growth is strong on the screen, the algae can get the carbon it needs from the CO2 in the air (instead of from the alkalinity in your water) after the CO2 in your water is used up. Thus the scrubber growth (filtering) is not limited by your alkalinity and CO2 in your water, and your alkalinity will stay at higher levels. This is compared to sealed chaeto reactors which don't contact air and thus must get all the carbon it needs from your alkalinity, which causes the alkalinity to drop faster.

When ordering the RAIN2, you can choose 1, 2 or 4 of the GEM5 lights, which will be already mounted to the inside of the dome lid cover. The GEM5 lights are also sold separately HERE and you can add them to the dome by using silicone glue.

Here are the differences in the RAIN2 units available:

Aquarium size: The RAIN2 with 1 GEM5 light has 24 square inches of 1-sided growth surface and is designed to be the only filter on an aquarium that is fed up to:

Each 50 pounds (23 kg) of phosphate-soaked nuisance algae problem rock counts for an additional 1 cube a day. The level of light of the 1 GEM5 light works well in saltwater when nutrients in the water are low. Up to 3 more GEM5 lights can be added at any time with silicone glue.

The RAIN2 with 2 GEM5 lights has 24 square inches of 2-sided growth surface and is designed to be the only filter on an aquarium that is fed up to:

Each 50 pounds (23 kg) of phosphate-soaked nuisance algae problem rock counts for an additional 1 cube a day. This medium level of light of 2 GEM5 lights works well when nutrients in saltwater are measurable. Having lights on both sides of the screen allow it to grow a few more days before the growth starts shading the algae roots. Up to two more GEM5 lights can be added at any time with silicone glue.

The RAIN2 with 4 GEM5 lights has the same growth surface area and feeding as with 2 GEM5 lights, but the high level of light of 4 GEM5 lights works well when nutrients in saltwater are high.

The amount of water in the aquarium, or the dimensions of the aquarium, are not important. If you feed more than the above amounts, you can use additional RAIN2 filters (or use our SURF, HOG or DROP filters) to add up to the amount that you are feeding, and then clean one of them at a time on a rotating schedule (one per week, etc). If you feed much less than these amounts, and the aquarium is very small, then it will still work but you just need to find a place where the filter will fit. It’s not possible to over-scrub.

Click the "image gallery" button above for more pictures, or click here:

Drain Pipe: Although a drain pipe is not needed, you can add one by using a standard 1” ID drain bulkhead which fits standard 1” (25mm) schedule 40 pvc pipe. The drain hole in the tray is 1 ¾” (44.5mm) diameter.

Head Room: If you are installing the RAIN2 in a sump or cabinet area with limited space, the RAIN2 will need 4" (10cm) above the top of the light-cover dome lid in order to remove the lid. However you can lift the whole tray unit up off of a pole mount [here], with as little as 2" (5cm) head room, and then remove the light-cover dome lid from the tray.

If you commonly have power outages, other waterfall scrubbers will dry out after a few hours, but you can prepare for and prevent this with your RAIN scrubber by placing it low enough in your sump (even slightly underwater if needed) so that when the power goes out the water level in the sump will rise up high enough to keep the screen under water. The GEM5 lights will not be harmed at all because they are designed for underwater use. With the screen submerged like this, it can last for several days with no flow or light. Do not try this technique with other waterfall algae scrubbers because it would be a certain electrical hazard.

The GEM5 lights can be put on a timer so that they stay on for part of the day, and off for the rest of the day, to possibly improve growth and filtering. However you can try 24 hours of light (no timer) if you like because sometimes it does work in saltwater with high measured nutrients such as more than 1.0 ppm phosphate. But generally, algae need dark time to rest.

The RAIN2 requires a water pump that can pump at least 200 gph (760 lph) water flow 24 hours a day. 300 gph (1135 lph) might be better to fill up all areas of the screen. The height (“head”) of the filter above the sump water level will require that the pump be able to pump up to that level and still be able to supply enough water. Generally, a 400 gph (1500 lph) pump with an adjustable output works in most cases. The water can also be fed from your display overflow; any type of overflow system (Herbie, siphon, etc) will work.

This RAIN2 will run on both 120V and 240V, and comes with a 10 ft (300 cm) power cord with a U.S. plug. If you require a different plug you can get an adapter at any local hardware or travel store, or online, or you can cut off the U.S. plug and install your own plug from a hardware store. It is a simple 2-prong plug, and no transformer is needed. Or you can use a laptop figure-8 cable; it plugs right into the power supply.

* Water Changes: If you have been doing water changes to reduce nitrate, phosphate, or nuisance algae, then an algae scrubber filter will greatly reduce the need for them and may possibly eliminate them. When algae grow in the filter, they consume nitrate, nitrite, phosphate, ammonia/ammonium, metals, CO2, and some toxins; so it’s just a matter of growing enough algae inside the filter to do the filtering you need, compared to how many nutrients you are putting into the tank with the food you feed (that is why the RAIN filter is sized for a certain amount of feeding per day). However, this filter (and algae in general) do not supply calcium, alkalinity, magnesium or strontium. So if you wish to reduce or eliminate water changes, you will need to supplement any calcium, alkalinity, magnesium or strontium that you were depending on water changes for. Freshwater aquariums, which may only need alkalinity (hardness) to be maintained, may get enough alkalinity from just doing evaporation top-offs with tap water from your sink.

The pole mounting option is recommended for the easiest and most sturdy operation, and is available separatelyHEREwhich has multiple height adjustments for cemented or non-cemented installations.

This RAIN2 comes with a 6 month warranty: Warranty is for replacement or repair only; not a refund. Costs for shipping back to us are not covered; you will need to ship the entire unit back to us before we can ship a replacement. Warranty is limited to repair or replacement, and does not cover fish loss, personal injury, property loss, or direct, incidental or consequential damage arising from the use of it. The warranty and remedies set forth above are exclusive and in lieu of all others, whether oral or written, express or implied. We specifically disclaim any and all implied warranties, including but not limited to lost profits, downtime, goodwill, damage to or replacement of other equipment and property, and any costs of recovering animals, plants, tanks or other aquarium related items and/or equipment. We are not responsible for special, incidental, or consequential damages resulting from any breach of warranty, or replacement of equipment or property, or any costs of recovering or reproducing any equipment, animals or plants used or grown with this product.

Can be shipped to any country; you can find shipping costs by using the shopping cart; be sure to click "display rates". If you don't have a zip code, enter "zip code" instead. Note that shipping outside of the USA will probably require you to also pay an import charge when it arrives. We cannot mark it as "gift". The lowest cost (but slowest) foreign shipping is generally USPS Priority Mail International, but USPS Priority Express International is faster. The size of the shipping box is 12 x 10 x 6.5 inches (33 x 23 x 16 cm) and the weight is 5 pounds.

Questions and Answers

"My 2-light version of the Rain2 has been working phenomenal I think it’s one of the best money spent on my tank, finally I keep control of my nitrates and phosphates, appreciate it and thanks for such an amazing product! In my case it helps a lot specially because I am handicap and only able to use one hand, so with the pole mount it’s a breeze for me to remove it to clean and harvesting the algae. Again excellent product" -- Simon Romero, Weston, Florida, USA...